Many businesses rely on large scale data processing systems for storing and processing data. The data in these systems is often stored as unrelated data volumes. These data volumes are often the working volumes of the data processing systems. Large scale data processing systems may receive requests from computer systems that require access to one of the data volumes. When the data processing system receives a request, one of the unrelated data volumes is accessed in a read or write operation.
At some point, it may be desirable to transform one of the unrelated data volumes into a point-in-time (PIT) copy of another data volume. In transforming one data volume, data is copied from memory that stores the one data volume to memory that stores the other data volume until the entire content of the other data volume is overwritten with new data. While data is being overwritten, write and/or read access is denied to both volumes involved in the transformation.